1. Field of the Invention
The field of art to which this invention pertains is tenter frames in general and, more specifically, it pertains to an improved opening wheel having an elastomeric rim for opening tenter frame clips mounted on an endless chain driven by a sprocket wheel, which clips are opened by moving the chain and, hence, an opening arm of each clip into contact with the opening wheel whereby to open such clip.
2. Description of the Prior Art
It is known, in the tenter frame art, to use an opening wheel as a means to open a tenter frame clip mounted on an endless chain carried by a sprocket wheel. The opening of the clip is brought about by moving the chain and, hence, a clip opening arm connected to the clip into contact with the wheel whereby a pivotable arm of such clip is moved into its open position, thus opening the clip. Typical of the prior art patents teaching the use of opening wheels of the type above described are U.S. Pat. No. 2,147,115 to Williams; U.S. Pat. No. 3,118,212 to Parkinson; U.S. Pat. No. 3,727,273 to Hyatt and U.S. Pat. No. 2,157,644 to Williams. In each of these patents tenter frame clips having a clamping surface and a pivotable arm for clamping a web of material therebetween are shown as being opened by bringing an opening arm of the clip into contact with an opening wheel having a metallic rim.
A problem with the teachings of this art, and with the other known art, is that the impact of the opening arm with the metallic, driven opening wheel is such that the useful life of the clip and of the wheel is greatly reduced. This is so not only because of the metal-to-metal contact but also, since the opening wheel and sprocket are driven together, due to the fact that such impact always occurs at the same location(s) on the rim, rather than being distributed around the rim.